1. Field of the Disclosure
The present disclosure relates to a laser display apparatus having a laser light source, and more particularly, to a laser display apparatus in which a speckle can be suppressed.
2. Description of the Related Art
Generally, laser display apparatuses can be easily applied to projection displays due to the collimation of a laser beam. Moreover, the intensity of a laser beam is greater than the intensity of light generated from other light sources, and thus a laser can be used to realize a clear, large screen image.
A laser display apparatus uses a laser with high coherency, causing speckle. Speckle refers to coherent noise randomly occurring due to high coherency of a laser light source.
For example, when an image illustrated in FIG. 1A is to be realized on a screen by a laser display apparatus, the image is realized as illustrated in FIG. 1B due to the above described speckle.
U.S. Pat. No. 5,274,494 discloses a “Speckle Suppression Illuminator” which purports to suppress the above described speckle.
The “Speckle Suppression Illuminator” includes a Raman cell, which is a chamber storing a gas for dispersing incident light, in front of light sources radiating coherent light with a first wavelength. Accordingly, the illuminator provides a spatially coherent and temporally incoherent laser beam to reduce the intensity and occurrence area of the speckle.
However, since a Raman cell is in the path of the light radiated from the laser light source, the optical structure of the laser display apparatus is complicated and the number of manufacturing processes and costs are high.